Cinematographic apparatus.



CINEMATOGRAPHICv EPAATU S.

APPLICATION 'man nmzo, 191s.-

PatentedSept.. 28, 1915.

3 SHEETS-SHEET l.

K w@ BAUERSFELD. CINEMATOGRA'PHIC APPARATUS.

APPLICATION FILED D'Ec.2o. 1913.

' Patented Sept..28, 1915 3 sIIEETs-sHEEIz.

MMM. @www WI BAUERSFELD.

` CINEMATQG'RAPHIC APPARATUS.

APPLICATION `FILE-D DEC. 20|` 1913.

Patented Sem. 28, 1915.

3 SHEETS-SHEET 3.

ITED STATES PATENT OFFICE. c WAL'ELHER BAUERSFELD, OF JNA, GERMANY, ASSIGNOR TO FIRM DF CAItL ZEISS.,

' j 0F JENA, GERMANY.

CINEMATGRAPHIC APPARATII S.

FELm-acitizen of th'e German Empire,'re

sidin'g at Jena, Germany, have invented a new Iand useful Cinematographic Apparatus, of which the following is a specification.

The present invention relates to cinematographic apparatus, in which, both when taking and when projecting the pictures, the film is continuously moved and in which optical means are-provided in order to prevent this movement ofthe film from cansing a Wandering of the image` on the film (when the photograms are being taken) or on the screen (during the projection of' the said photograms). The opticalineans for this compensation consist usually of' a rota- 'table drum placed inthe path of' the rays.

which is fitted with a ring of optical members, c. g. lenses, prisms or reflectors, and 1s rotated umformly, so that. the traversing speed of the lihn and the angular speed of' the drum being correctly chosen, a stationary image is obtained; It is. however, well known, that with` the .etisting constructions 'of the said compensating drinn a perfectly stationary and constantly sharp -imagc cannot be. obtained. There still remain small movements and places where the imagepoints are not sharp. particularly in lthe outer parts of the image, which may cause a flickering ofl the image; this, with-the majority of such constructions the luminosity of the image is not constant, but decreases considerably in the transitional position of two images. According tothe present invention these drawbacks Inay be in part (i-onsidcrably reduced and in part entirely removed, by fitting the con pensating drum with a ring of central reflectors. A central, reflector consists, as is well known, of' three plane reflecting surfaces,` which are perpendicular to one another, and `has the property` that object and A fcflectcd innige occupy Isuch a position with respect to the center of the reflector that the vconnecting line between veach object point and its .corresponding point in thc imag(` passes through the center of the rcflector and is halved by the said center. Ilencecach ray, which enters at any desired ,inclination to thereflcctor axis and with any desired yorientation ,with regard tothe reflector, will emerge, after being reflected at Specification of Letterslatent.

In addition to.

Patented Sept. 28, 1915.

Application led December 20, 1913. Serial No; 808,005.

i all three reflecting surfaces, in a parallel but regard to the reflector the 'same amount in parallel direction toward theopposite side; on the central reflector being displaced simultaneously7 at half the speed in a direction of motion parallel to thatof the object, there results an image, which is stationary in all points relative to space. An inc'idental simultaneous rotation of the central reflector about any aXis has no influence on the production of` the stationary innige, pro vided only that the elfectiverays are reflected at all three reflecting surfaces, as the position ofthe image depends only on the positini for the .moment of thc center of' the reflector. Hence, when utilizing' centra-l 11efiectors for the optical compensation of the wandering of the image in-cinematographic apparatus, an absolutely stationary image may be obtained. when the center of the rcflector and thc film are moved in parallel paths. the speed of travel of' the former bel ing h'alf that of the latter. .As an accurately reclilineal guiding of the center ol the reflector presents constructional difficulties, it will suffice in practice to replace the straight line by the arc of a circle, the central' reflectors being fixed on a drum of so large a radius that tangent and arc coincide with suflicient accuracy on the section in use. Such a drum is disposed at asuit` able place, c. y. between objective and film, in the path of' the rays ofthe cinematographic apparatus. for instance in such a manner that the axis of rotation ot' the drum lies in that plane. which passes perpendicularlyto thedircction ol' motion of the film through the center of the film-window. It may also b e recommended from constructional reasons` to layrthe axis of the drum parallel to the plane of ,the film and correspondingly to dispose the optical axes of the central reflectors substantially radially to the axis of thedrum. When the central rcflector consists vof' plane Areilecting plates, v'. e. when the space within the reflector filled withai'r, thel center of thc reflector,l which determines the position of the reis fe L-ioiiis complied wih iii sentii when h of die reflecting uifaces ii'liiiieiisioiied so as im Coii'spond o'he size the p iciue; the second coidiioii can 33@ iifilied :i simple manner by :i iiiiphiagin u Hiv invention .i'iii undivided cviiiiu i ii@ lili( ir i. in ili'iin'n iii l'iiil -into the corresponding position shown by dotted lines. Hence the refiectin would obviously have to be move same sense, in whifthe object point moves, however at half the speed. Should the reflecting prismbe moved not in a straight'line,

prism but, as would in practice be usually the case,

- and image point at all. The movement of the prism perpendicular to the line Y would Shop1 `\itself in such a manner that the image point, while always lying on the straight linje C3 D3, would make small movements inythe direction perpendicular to the line Z Z. Hence, as was mentioned farther back in this specification, the radius of the circle, von which the central reflectors move,

will be so chosen that the section in use ofthe circumference of the circle approximately coincidesl with the tangent.

In Figs. land 2 a drum-body a,the shaft' b of which is rotatably journaled, reflecting prisms c, which` are contiguous to one another on the periphery of the said drum, are. mounted in such a manner that all the reflector centers .lie ina plane, which `is perpendicular to. the drum-shaft b. Lateral'ly of the drum andV in front of the opening of the central reflectors there are shown by dotted lines a stationary projection objective marked d and the film e, as well as an actuating wheel f, by which latter the film is larlyV to the drum-axis.

traversed at a constant speed perpendicu- An illuminating arrangement is 'indicated by the lcarbons g1 and g2 of an electric are lamp, a condenser system h1, h2, a reflecting prism i and a filmwindow Ic, which limits the size of the i-mage. Themotion of the film-traversing wheel is positively transmitted to the 'drum a. by

. simple reflectingpr-isms nl and `the-ridge` In Figs. 3 and 4 'each central-reflector. 1s

A drum body. a carries, rigidly fixed to it, two plano-parait` lei, annular glass disks-a1 and a2, toA whichthree toothed wheels Z, mand n, which are shown` in Fig. 1, the ratio of gearing being yso chosen that the rotator-y speed of the'optical reflectorcenters .is half. asgreat as the traversing speed of -the film. The objective fl formsin the lane X,X of the screen an image of the fi 'm pictures. moving past in front of the lilm-ivindowls, which image is stationary in all points relatively to the fsetsof prisms, adapted tov vary the optical vlength of the path offlight.

. 'wALTHnRBaUEnsFEL-D.

screen and is of constant luminosity.

divided .into two.' parts.

the two-.parts of the central reflectors,l the in the prisms c2, ar cemented; the whole system is carried by a shaft b, which is rotatably journaled in a casing b1. Laterally ofthe drum there vis again indicated in front of one of the rings ofprisms a stationary lobjective d and in front of the other ring of prisms a uniformly Vmoving 4filin e. The film traversing wheel f, which consists of a disk, not shown in Fig. 3,- and of a traversing rim f1, is in this case fixed coaxially te the drum,

so that the otherwise necessary transmission of motion is done awayivith, and-hence .the film and the reflector drum always move in exact unison. An :1r/rangement similar to that shown in the first example is provided for the illumination ofthe film pictures.

Between the two glass disks a1 and a2 there are further in a stationary casing 0 two glass wedges p1 and p2, which are in contact with one another, the outer surfaces of. which' are perpendicular to the axialray and one (p2) of which can be displaced relatively-to the other by means of a screw g, for thev purpose of making the optical length' of the path of light and.. by this means the rotatory speed of the optical centers of the reflectors vawedges against each other, so that in spite of the displacement they are always in contact with one another. y

' I claim:

riable. Two springs 111 and r2 press the glass 9 1. In a cinematographic apparatus the 195 combination with a constantly moving film of a constantlymoving reflector drum,which is provided at its periphery with a set of evenly spaced' central reflectors', each such central reflector containing three plane ref.

flecting surfaces, which. are perpendicular to one another.

2. Ina cinematogra-phic apparatus the' combination with a constantly moving film ofa constantly moving reflector drum,which is provided at its periphery with a vset of evenly spaced ntral reflectors, consisting each of two separate parts, asimple reflect.

ing prism and aridge prism, both of which parts are fixed to the said drum; i l 1 v3. In .a cinematographic apparatus the combination with a constantly moving film of a constantly moving reflector drum, which isv provided at its periphery .with a Aset of evenly spaced central reflectors, consisting each oftwo. separate'parts, a"simple reflecting prism. and a ridge prism, fixed to the ysaid drum, and adjustable glass wedges being disposed lin jthe space between the two Witnesses: l PAULLKRGER, I

RICHARD HAKU. v 

